Steelers coach Mike Tomlin confirmed Tuesday that Polamalu sustained a concussion while tackling Cincinnati Bengals running back Cedric Benson on Sunday, the same play on which cornerback Bryant McFadden broke his right forearm. McFadden is expected to be out at least a month.
Despite Polamalu's history of concussions, he may not miss any playing time.
"Tests are favorable at this point, he's slated to practice tomorrow [Wednesday] and we'll see how he goes," Tomlin said.
Pro Bowl running back Willie Parker, out for three weeks with a knee injury, may also return for the matchup of first-place teams with 5-1 records.
Tomlin says Parker will practice starting Wednesday.
Parker has a sprained left knee and has not played since
Pittsburgh's lone loss of the season in Philadelphia on Sept. 21.
Parker was on track to return Sunday against Cincinnati before
aggravating the injury during practice early in the week.
Tomlin says if Parker doesn't have any setbacks this week, he
will start Sunday.
The Steelers are hoping for the same for Polamalu. His sometimes reckless tackling style in which he launches headfirst into a ball carrier has made him susceptible to concussions, although this is Polamalu's first in the NFL since he was hurt tackling the New Orleans Saints' Reggie Bush on Nov. 12, 2006.
In that game, Polamalu was so woozy he almost tumbled off the team bench after being injured. Bill Cowher, then the Steelers' coach, said afterward it was Polamalu's first NFL concussion, and the safety returned to play against Cleveland the following week.
According to previous interviews with Polamalu and published reports during his career, Polamalu had at least three concussions while at USC -- each during practices or scrimmages -- and two while playing high school ball in Oregon.
Tomlin defended the four-time Pro Bowl player, saying he has not detected anything unusual or careless about Polamalu's tackling style.
"No, he's not any more reckless than anyone else playing the safety position," Tomlin said Tuesday. "This is a guy who runs to the football and sometimes violent collisions happen. He has his share of them. But it's not any negligence on his part in terms of technique."
Only last week, Polamalu criticized the NFL for constantly leveling fines against players involved in hits the league determined to be potentially dangerous, arguing the league was becoming "flag football, two-hand touch."
The decision whether the four-time Pro Bowl safety plays Sunday is up to team doctors, Tomlin said. The Steelers, as do other NFL teams, don't allow a player to return from a concussion until he passes a series of tests that compare cognitive skills before and after a concussion.
Doctors and researchers working in the same medical complex where the Steelers train helped develop the tests.
"That decision is very easy, we simply do what the doctors tell us to do. Right now the tests are favorable, and we will continue to test him throughout the week," Tomlin said. "Those decisions are always easy because we leave it up to the professionals."
Before Polamalu became one of the NFL's top defensive players, friends and coaches said they were concerned about Polamalu's tendency to lead with his helmet occasionally. Such tackling is discouraged at all levels of football, and the NFL places signs inside locker rooms warning against it.
Polamalu's pre-NFL concussions concerned the Steelers enough before they drafted him in the first round in 2003 that he underwent a pre-draft neurological exam. He was cleared by Dr. Joseph Maroon, a neurological surgeon who has long worked with the Steelers and western Pennsylvania high school and college teams on safety issues.
McFadden had surgery Monday to repair his broken forearm -- a stabilizing plate was installed -- and Tomlin said he will be evaluated after a couple of weeks.
With McFadden out, former starter Deshea Townsend will return if he is healthy. Townsend has played sparingly since bruising his heel in the season opener. William Gay, who has never started an NFL game, would likely play if Townsend can't go.
"We've got a lot of confidence in him," Tomlin said. "He's in that second-year player group we place a lot of pressure on to take that jump."
The Steelers lead the AFC North by two games and the Super Bowl champion Giants own a half-game lead over Washington in the NFC East.
Information from The Associated Press contributed to this report.